As kids, Jimmy Markum and Sean Devine watched their best friend, Dave Boyle, disappear down the street in the back of an unmarked police car. Or so they thought.

Four days later they learned the truth: Boyle, who'd supposedly been picked up for destroying municipal property, was actually abducted by a pair of pedophiles. He eventually escaped, physically at least, on his own.

Thirty years later, Devine (Kevin Bacon) is in the homicide division of the Massachusetts state police, Markum (Sean Penn) is an ex-con convenience store operator and Boyle (Tim Robbins) is an underemployed, slightly boozy husband and father of one, still living, as does Markum, in the old neighborhood, a working-class section of Boston not far from the Mystic River.

But the image of Boyle disappearing down the street in the back of the old sedan is still with them -- and it quickly bubbles to the surface when Markum's 20-something daughter turns up dead.

Yet as complicated as that all seems, it's only the opening salvo of Clint Eastwood's award-winning film Mystic River, which seems to find no end to the depths of misery suffered by each of its protagonists.

Boyle, of course, has the longest and most visible scars, best captured in his slightly hunched-over walk. His shame is gone, but not forgotten, as evidenced by the difficulty he has, despite his best efforts, relating to his wife (Marcia Gay Harden) and son, Michael (Cayden Body), or his inablity to tell the truth or even offer up consistent stories about why he came home bloodied the night Katie was killed.

Still, he can't seem to outsuffer Markum, whose loss of his first daughter draws him back into a paradigm of bloodletting and revenge worthy of the worst Shakespearean lord.

And between them is caught Devine, who doesn't want to believe that Boyle, for all his problems, would have murdered Markum's daughter, despite an ever-tightening noose of evidence.

But for all its plots and subplots -- enough to stoke a soap opera for an entire season -- it's ultimately the acting that carries the day in Mystic River.

Penn, who took home an Academy Award for best actor, is at his intense best as Markum, a character so torn to pieces by the loss of his daughter that your heart can't help but go out to him -- until the investigation brings out more and more of the dark secrets of the intervening years.

Meanwhile, Robbins, who won an Oscar for best supporting actor, works in just the opposite mode: he's the cinematic realization of Henry David Thoreau's "quiet desperation."

And in his own way, Bacon tops them both. Gone is the arrogant punk of Diner or The River Wild. This Bacon sees all but knows little and lords nothing over anyone. For that alone he should have received an Academy Award nomination as well.

Eastwood, who was nominated for a best director Oscar, is at the top of his form, too. He gives Mystic River a somber look, muting the tones and accenting the grays that hang over Buckingham Flats. Eastwood also takes credit for the musical score, which adds yet another layer of quiet dread to the proceedings -- not that any was needed. Mystic River is darker than any film noir to come out of Hollywood in its heyday.

But that's hardly to its discredit.

True, Mystic River won't work as a "date flick," unless of course you happen to be seeing a clinical psychologist. On the other hand, if you're one who likes to plumb the depths of the human soul, this is one long ride you'll never forget.